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contribution by Welles

...
Macbeth, Welles went to Italy, where he acted as the 18th-century charlatan and magician Cagliostro (and directed a few scenes) in Gregory Ratoff’s
Black Magic (1949). He starred in other films, including Henry King’s
Prince of Foxes (1949), as a colourful Cesare Borgia, and most famously Carol Reed’s classic...

discussed in biography

...London; Peggy Cummins played a chorus girl who suspects a wealthy man (Victor Mature) of killing her roommate. Ratoff’s period drama about the 18th-century magician Cagliostro,
Black Magic (1949), was even better, with lead actor Orson Welles codirecting it uncredited.